2009-02-07

Spirit Sol 35

Today was the most messed-up sol ever. It did pretty much come together at the end, though.

I come in early for the traversability meeting. I'm about five minutes late for it, but I can't stand not knowing what happened yestersol, so I check in quickly with the mobility/IDD team. The news is alarming. Literally alarming: the spacecraft has sent nothing but alarms, called "warning EVRs," during the current downlink pass. These are relatively high priority, so they tend to squeeze out other data. As a result, the documentation imagery didn't come down yesterday, but fortunately we didn't need it -- we got the contact switch states, which is all we needed for the go/no-go decision on using the RAT, and Jeng stuck his neck out and said go. (He's naturally nervous about this, but he was absolutely right, and probably saved us half a sol -- two million bucks.)

Then we started getting the warning EVRs. Every time one shows up, every workstation in the SMSA beeps. We're getting thousands of them, so the workstations are constantly beeping. My explanation is that our little drama queen is jealous of her younger sister's recent successful drive, so she's throwing a tantrum. The more literal explanation, it turns out, is a flight software bug that thinks an IDD joint current limit is being violated when it isn't. The result is that when we use the RAT to grind, which is happening now, two of these warnings are generated every second. Which means two beeps per second per workstation (there are dozens of workstations in the room), during several hours of grinding. In total, we get something like 30,000 of these warnings. Some people are freaked out by the warnings, especially before we find out that they're not a big deal, but it's possible to look at them as a good thing: they confirm that the RAT is working. Then again, it's easy for me to say that. I don't have to sit there and listen to them.

So I don't. Instead I go to Art Thompson's traversability meeting, which is being attended by relative bigwigs like Arvidson and Adler. I catch the tag end of Randy Lindemann's analysis of the slippage encountered by Opportunity, which basically says that the slip is moderate on flat ground (about 5%, well within our error budget) but rises dramatically, to 90% or so, at 20 degrees of slope. Opportunity will have to work hard to climb out of her crater.

The rest of the meeting is about Spirit's drive. The good news is that this is still on the plate, despite the EVRs -- assuming we get enough non-EVR data during the later pass to plan for the following sol. I talk them through the current plan. I'm getting a lot more confident at this -- when I look at myself objectively, I actually seem to know what I'm talking about.

After tomorrow's drive to White Boat, the plan is to head straight for Bonneville, passing as close by the lander as possible so that they can image the LEGO astrobot as we pass by. (This is actually a scientific experiment: the astrobot is surrounded by magnets that help us determine the magnetic properties of the Martian dust.) During the drive, we're going to shoot for 20-25m per day at first, then push that as far as possible, maybe up to 40-50m per day. We might even push to do two drives a day -- drive as far as we can safely see for the first drive, take imagery, then have another rover driver come in during the day to analyze the images on the fly and plan a second drive for the same day if possible. This is aggressive. I like it.

At the end of the meeting, Art shows a recently acquired PANCAM image of the drive direction. It's a gorgeous image, but my attention is drawn to the feature names. Ripple City. Downtown. Morpheus Hollow.

After that meeting I have about an hour before the downlink assessment meeting. Tomorrow's already shaping up to be a complex day, and there's no downlink data to look at yet because of all the EVRs, so I get a head start on the sequencing. The goal is to have a reasonable prototype drive by the downlink assessment meeting so I can show it to the scientists. I get this done, and on the way to the meeting I run into one of the scientists, who says, "Hey, you're the one who saved the RAT guys' bacon yesterday, huh?" I hope so, I tell him, but we haven't seen the image yet.

At the downlink assessment meeting, the RAT PUL is careful to point out that they need the post-grind image of the magnets as well. They've learned yesterday's lesson.

I show the scientists the prototype drive. I'm surprised at how calm I am. The last time I did this I was unaccountably nervous, but I seem to have found my center. The demo has its intended effect, getting everyone on the same page and prompting useful discussion about what tweaks they're going to need to the sequence. At their request, I look into whether it will be possible to MTES the soil we were sitting on for the last two weeks. They want an MTES just after we drive off, and another at the end of the drive -- two observations about an hour apart, if possible. But it turns out that because we're looking backward over the rover's body, the solar panels get in the way, so we won't be able to get the first image until the drive is almost complete anyway. So we'll take the first MTES at the end of the drive, and the second of the pair tomorrow morning, or so we hope.

I'm about to leave, but Rob Manning comes in to report on the state of the spacecraft -- it's his first day as a surface mission manager. Rob manages to chill everyone out about the EVRs, which is a good trick. He's just got the personality for that kind of thing.

Before the SOWG, I have to go over to the testbed, where Mark Maimone is, to refine our estimate of the data volume we'll be generating. We've been claiming 50 Mbits, which is a huge number, and we want to cut it down if we can. There are only 15 minutes until the meeting, so I literally run all the way across Lab, get our estimate down to about 35.5 Mbits (we decide to tell them 40, to leave ourselves some margin), and get back just in time to be late for the SOWG meeting. I hate being late, for a start, and by now I'm starting to get stressed out about getting everything done -- especially because they've decided to squeeze a fair amount of IDD work into the morning, so it's not just the drive I have to cope with. On top of that, Art has decided that we need to run the drive sequence in the testbed before we can uplink it, which is going to eat all of my sequencing time and then some. So while the SOWG is working, I'm trying to get as much sequencing done as possible, so I'm not really listening and I have to ask them to repeat all of their questions for me. The SOWG really needs 100% attention -- not 99%, and definitely not the 20% I'm giving it now. At this point I do not have it together any more.

When the SOWG is mercifully over, I gobble down half of a cold sandwich as I get my sequence IDs assigned and write them down on Post-It notes I stick on my workstation. That way they won't have to call me in the testbed for the IDs, though I leave the testbed number anyway. Art has somehow sweet-talked Mark into agreeing to stay around to run the drive sequence, so he and I try to set things up. We upload the sequences to SSTB[1] and maneuver it into a good starting position, but the SSTB-Lite rover is uncomfortably close to our final position. So Mark tries to tell it to move, and that's where the ISIL[2] time warp starts to kick in. Before I know it we've been there three hours -- this is when we were planning to leave -- and we still haven't gotten started. SSTB-Lite is refusing to move and it's too heavy to push. Mark is running outside every five minutes to get cell phone reception, calling everyone he knows, slowly getting closer (we think) to a solution. Meanwhile, emissaries from the Sequencing MSA are showing up to ask questions (one of which I decide by, literally, flipping a coin) -- because, as it turns out, the ISIL phone is strangely out of order and, of course, cell phones get no reception in the ISIL itself. Eventually Art starts to get worried about the fact that we're falling behind schedule, so we arrange for one of the scientists to come take my place and I go back up to the Sequencing MSA. Thanks to the ISIL Effect, I've gotten nothing done for three hours, and I was behind when I went down there.

Fantastic.

Fortunately, Bob Bonitz has already shown up and is making good progress on the IDD part of the sequencing. So we split it: I'll finish up the drive sequence (on the assumption that it will eventually work in the testbed -- if it doesn't, we're screwed), and he'll take the IDD. This will be a solution. There's too much left for either of us alone, but if we split the work we'll make it.

Which we do. With only half as much work to do, I almost finish before the activity plan approval meeting ends -- at least I have a good animation to show at that stage. Relief ensues.

I'm far enough ahead that I can actually watch the midnightly science briefing, which once again has incredible results. I've been hearing about the results of our RAT grind all day, but I haven't had a second to look at it until Matt Golombek brings it up on the screen. It's a remarkable image, showing different colors (though we won't know what the colors are until after tomorrow's MI sequences, the ones Bob is building the IDD motions for now) and possibly different minerals in a single shallow hole a couple of inches wide. There's a definite ring imprint from the rim of the RAT, and chips have flown off of the RATted surface, which would tell me something about the composition of the rock if I knew stuff like that. Or maybe it wouldn't: the scientists are scratching their heads over it, too.

Matt also shows the same image Art had up at the traversability meeting earlier, and he points out a clear dust devil track we'll cross on the way to Bonneville. Matt spent three years worrying about the landing sites -- that was his big job on this mission -- and he's beside himself with joy about both of them. The dust devil track we're seeing is exactly the kind of thing he wanted from Gusev.

Last of all, Matt shows what is "without question the coolest picture yet taken." It's an Opportunity PANCAM of part of the outcropping, showing a white rock with little blue buckyballs weathering out of it. To steal Art's observation, they look like tiny blue clown noses stuck to the rock. Probably, they're part of the rock's interior, and as the rock weathers it exposes them. Because of the filters used in this image, the blue is exaggerated, but they really would have a bluish tinge as seen in natural light.

The preliminary conclusion is that that's the hematite. Whatever it is, it's in chunks the size Phil Christensen said the hematite would be, small enough to be blown around by the wind. If it is hematite, though, nobody knows what would give it this form. Since this view is of a relatively hematite-deficient part of the crater, the hypothesis is that we'll see more of the buckyballs as we scan the area to the left.

I print out copies of this image for myself and for Scott Doudrick (who says that at ECAP[3] time he's just going to mail a copy of this picture to his supervisor and say "What else could you need?"). When browsing for it, I also find the picture I was waiting for all day: the PANCAM of the RAT magnet. The RAT guys got their image. Scott saved the day.

[1] Surface System Testbed. This term is (as here) usually a shorthand for the SSTB rover, our Earth-bound pseudo-copy of Spirit and Opportunity that we drive around in our testbed. There's also the SSTB-Lite rover, which is missing an arm and a camera mast but is still useful for testing mobility.

[2] In-Situ Instrument Laboratory, the official name for our testbed facility.

[3] Employee Contribution Assessment and Planning, or something like that. It's the JPL term for our annual performance review, an activity that, incidentally, I despise.